This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Cupredoxins comprise a class of Type I blue copper proteins that participate in respiratory, anabolic and catabolic processes in plants and bacteria by mediating biological electron transfer (ET). Amicyanin belongs to a distinct class of cupredoxins found in bacteria, which differs from its closest relatives, plastocyanins and pseudoazurin, by having 20 additional residues at the N-terminal region. Amicyanin contains a copper-binding site with two histidine, one cysteine and one methionine side-chain providing copper ligands. Amicyanin mediates ET from methylamine dehydrogenase , a quinoprotein containing the tryptophan tryptophylquinone as prosthetic group, to c-type cytochromes.